Because it’s designed to accommodate multiple users, easy networking and always-on connections, OS X is very secure, more so then a Windows PC. As we’ll see, other users (and outsiders) have only the level of access that you grant them. However, this can be both a strength and vulnerability, in that you could be fooled into giving a rogue users or application access privileges. This is what happened with the Flashback Trojan in early 2012 (a trojan being a type of malware that masquerades as something innocent to trick you into installing it).
Mountain Lion includes a new, extra layer of security in Gatekeeper, which can authenticate applications and prevent software from unknown sources running. This provides a key way to stop such malware.
You can set Gatekeeper to one of three levels.The most secure permits only software that’s been downloaded from the Mac App Store to instal and run. All programs in the Mac App Store have been fully vetted, so you can be confident that they’ll be safe. The next level includes software from other well known and trusted sources in addition to the App Store. Finally, you can set Gatekeeper to allow software that’s come from anywhere. This is the least secure, but if you have specialist software then you may need to use this setting to enable it to download, install or run.
Alternatively, you can manually exempt a specific application from Gatekeeper without needing to lower your security generally. This is useful if you need to run a specialist piece of software that you trust. To do this right-click the program’s icon in Finder and select Open from the contextual menu that pop up. Click Open again. If necessary provide your username and password. This overrides the normal level of security provided by Gatekeeper and will enable the software to run and install.
If you try to run software that doesn’t match your Gatekeeper settings, you’ll get an alert and won’t be able to run it unless you change your Gatekeeper settings or opt to open it as an exception. This makes it very difficult for malicious software to run without your full knowledge.
How To Configure Gatekeeper
- Security and Privacy > gatekeeper enables you to keep your Mac more secure by restricting what software can run on it. To configure Gatekeeper, go to Apple → System Preferences and the select Security and Privacy from the list of options available. Click the General tab.
- Unlock Changes > before you can make any changes to the security options on your Mac, you need to unlock them. Click the padlock in the bottom left of the window and enter an administrator username and password when prompted. This removes the lock.
- Pick and Choose > You can now pick what types of apps are allowed to install and run. For the utmost safety, restrict them to Mac App Store. For greatest flexibility but least security, choose anywhere. Click the padlock to lock these changes in place until it’s unlocked again.